Zhang Juping, Yao Jian, He Kunrong, Yu Chunlan, Du Jie, Du Jiancan, Fu Qiantang, Yao Ruifeng, Howe Gregg A, Han Xiao, Hu Yanru
CAS Key Laboratory of Tropical Plant Resources and Sustainable Use, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Kunming, Yunnan 650223, China.
College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China.
Plant Cell. 2025 Aug 4;37(8). doi: 10.1093/plcell/koaf178.
Seed size is crucial for crop yield and plant ecological fitness. The phytohormone jasmonate regulates Arabidopsis thaliana seed size, but the underlying molecular mechanisms remain elusive. Here, we established that CORONATINE INSENSITIVE1 (COI1)-mediated jasmonate signaling acts maternally to repress seed growth. Accordingly, jasmonate signaling suppresses the expression of KLUH (KLU), encoding an inducer of integument cell proliferation. KLU regulates the effects of COI1-mediated signaling on seed size. The JASMONATE ZIM-DOMAIN (JAZ) repressors of jasmonate signaling interact with SUPPRESSOR OF DA1-1 (SOD7) and DEVELOPMENT-RELATED PcG TARGET IN THE APEX4 (DPA4), two transcription factors that directly repress KLU. Overexpression of SOD7 largely rescues the seed size phenotype of coi1 mutants and JAZ1-overexpressing JAZ1-ΔJas plants. Furthermore, SOD7 associates with MYC2 and MYC4, two master transcriptional regulators of jasmonate signaling. SOD7 and MYC2 synergistically decrease KLU transcription and inhibit seed growth, while JAZ1 interferes with their transcriptional activities and physical interaction. Notably, jasmonate signaling considerably impacts seed size under salinity stress, primarily through SOD7 and KLU. Collectively, our findings suggest that the JAZ repressors and MYC transcription factors of the jasmonate signaling pathway coordinate with the SOD7/DPA4-KLU pathway to incorporate jasmonate signals into seed development.
种子大小对作物产量和植物生态适应性至关重要。植物激素茉莉酸酯调节拟南芥种子大小，但其潜在分子机制仍不清楚。在此，我们确定了CORONATINE INSENSITIVE1（COI1）介导的茉莉酸酯信号在母体中发挥作用以抑制种子生长。相应地，茉莉酸酯信号抑制KLUH（KLU）的表达，KLUH编码珠被细胞增殖的诱导因子。KLU调节COI1介导的信号对种子大小的影响。茉莉酸酯信号的JASMONATE ZIM-DOMAIN（JAZ）阻遏物与DA1-1的抑制因子（SOD7）和顶端4中的发育相关PcG靶标（DPA4）相互作用，这两个转录因子直接抑制KLU。SOD7的过表达在很大程度上挽救了coi1突变体和过表达JAZ1的JAZ1-ΔJas植物的种子大小表型。此外，SOD7与茉莉酸酯信号的两个主要转录调节因子MYC2和MYC4相关联。SOD7和MYC2协同降低KLU转录并抑制种子生长，而JAZ1干扰它们的转录活性和物理相互作用。值得注意的是，茉莉酸酯信号在盐胁迫下对种子大小有显著影响，主要通过SOD7和KLU。总体而言，我们的研究结果表明，茉莉酸酯信号通路的JAZ阻遏物和MYC转录因子与SOD7/DPA4-KLU通路协同作用，将茉莉酸酯信号纳入种子发育过程。
